1. Field of the Invention
This invention relates to a reclosable pour opening structure for a packaging container and, more particularly, to an opening structure comprising a panel section enclosed by an opening boundary line on the panel which panel section is removable from the panel to provide a pour opening therein, and further comprising a cover foil overlying the removable panel section and liftable from the panel in the region of the opening boundary line, the cover foil being connected through an inseparable union both with the panel at a junction situated outside the opening boundary line and with the removable panel section, so that lifting of the cover foil will cause the removable panel section to be lifted and lowering the cover foil to its original position will cause the removable panel section to reenter the pour opening to reclose it. The invention also relates to a method of making such an opening structure.
An opening structure of one-way packages should meet the following requirements:
(1) Permit easy opening and reclosing;
(2) Permit hygienic and non-splashing pouring of the contents from the packaging container;
(3) Not cause accumulation of dirt during shipping and storing of the packaging container;
(4) Be simple and inexpensive to produce;
(5) Require little space;
(6) Upon opening, no part of the opening structure should be detached from the packaging container.
2. Summary of the Prior Art
Exemplary embodiments of opening structures of the above-defined kind are shown in U.S. Pat. Nos. 3,133,689 and 3,438,565. In these prior art opening structures the cover foil is made of the same material as the panel of the packaging container; in fact, it is integral with the panel. The thickness of the cover foil thus is always equal to the thickness of the panel material, and if the panel material has a considerable thickness, the opening structure may therefore be undesirably bulky. Moreover, the strength of the inseparable union of the cover foil with the panel is dependent on the strength of the panel material. Although this union could be designated as "inseparable" in the sense contemplated in this application, because it is not intended, and indeed not very easily possible, to detach the cover foil completely from the panel when the opening operation is carried out, a complete tearing off of the cover foil from the panel may not always be avoided.